Need to sleep better? Have questions about your pregnancy? Want to break a bad habit, exercise more or clean up your diet? These apps can help:

Sleep Smart Alarm Clock This app (by Proactive Life LLC) uses your phone's accelerometer to track your body movement and determine your phases of sleep. It uses audio signals to enhance deep sleep, then times its alarm to gently rouse you during a light sleep cycle - which means you wake up feeling refreshed, not groggy. For iOS. 99 cents

SmokeFree If you're trying to quit smoking, this app can offer encouragement along the way. SmokeFree tracks the time since your final cigarette and tallies how much your health improves - and how much money you've saved - with each smoke-free day. For iOS. $1.99

Totally Pregnant This brand-new app helps you know what to expect each week of your pregnancy. Videos and 3-D animations show how the baby develops over time, and week-by-week tips and information address topics such as morning sickness and stretch marks. Live courses, discussion groups and video blogs help you connect with experts and other expectant moms. For iOS and Android. Free, but the app charges for some content.

Substitutions This app (by Gormaya) helps you alter recipes to meet your - or someone else's - dietary needs. Find the right substitutions to make a recipe low-fat, low-sodium, gluten-free, vegan-friendly, safe for people with an allergy and more. For iOS. 99 cents

Fitbit You don't have to have a Fitbit to use the Fitbit app. The wildly popular motion-tracking device recently updated its app for the iPhone 5s; now the app uses the M7 chip in your phone to track your steps, distance and calories burned. It's not quite as accurate or thorough as having a Fitbit attached to your body, but it's a good way to start - and to figure out whether a fitness tracker is for you. For iOS. Free

Coach Alba: This actually isn't an app; it's a health and fitness coaching service offered through texting. To help you make a lifestyle change, Coach Alba will send reminders and support messages to get you through those weak spots in the day when you crave a cigarette or a late-night snack. You can interact with the service and get tips, ideas and encouragement. Coachalba.com. $29.95 per year